That sounds like an OpenGL issue that some people are seeing once in a while. I’m not sure yet about the cause of it or the solution, although if you’re rendering with OpenGL you could try turning that off and see if it makes an improvement. (Set “Fast Previews” to a setting that doesn’t use OpenGL, and don’t have “render with OpenGL” checked in the render settings.
It would be good to know if this only happens with multiple instances of pIAE, with specific emitters, etc.
Please email support at wondertouch dot com with the results of this, and with your system specs and any other info that may be helpful.
Alan.
http://www.wondertouch.com